Panasonic RP-HT710 and Sennheiser HD 419
(flat-plate measurements)
Two popular "dirt-cheap" headphones from the past. The "borderline" category of headphones.
February 16, 2025
The following is a measurement of two headphones that are no longer available in stores. These headphones represent a "borderline" category between hifi and budget: too valuable to be in the budget category, but far from an "audiophile's dream".
The measurements are simple flat-plate measurements, nothing special. With this method, we measure the headphone cup + driver frequency response, which is acceptable for large (over-ear) headphones.
One of the drawbacks of flat-plate measurements is that the leakage is higher with real or silicone ears than with flat-plate. As a result, bass response is overestimated in flat-plate measurements. Flat-plate measurements can be (and should be) supplemented with silicone ear measurements to get a better picture of low frequency performance.
The correction curve is obtained by subtracting the frequency response from the reference or target curve (it's enough to mirror the frequency response to the zero dB axis above 150 Hz). In most cases, it is impossible to correct response errors with a simple bass-mid-treble type equalizer, so a parametric equalizer or an equalizer with at least 15 bands is needed. (Voicemeeter - a free EQ, mixer and booster for Windows.)
The basic rule of EQ correction is to avoid boosting frequency bands by more than 6 decibels, especially below 100 Hz (distortion...). If more than 6 dB boost is needed, it's worth looking for another solution.
Panasonic RP-HT710
I wonder how many Panasonic RP-HT710s are left in good condition (if there is any...). These headphones were a big hit around 2005, good value for money, but their sound... The bass performance is weak, and the treble range is boosted. These headphones are not good to listen to without a correction EQ. On the other hand, we can't complain about the build quality and comfort. These headphones are sensitive and easy to drive, so they can be played at very loud level from an output with 1 VRMS maximum voltage, even after equalization. The channel matching is poor, there is a fairly large (two decibels) difference between the two sides, but the correction is easy with a "balance pot".
This headphone has "angled drivers", which is not common in this price range. The "angling" has a subtle effect on the concha response.
This is what a Panasonic RP-HT710 looks like:
Equalization has dramatic effect on the tone.
Sennheiser HD 419
The same can be said about the HD 419. It has better bass performance, but its sensitivity is a bit lower and the distortion is high below 100 Hz at high volume. This headphone doesn't like bass boosted or "bass heavy" material.
Csaba Horváth
See also:
Headphones & amplifiers - output impedance, load impedance and frequency response
High-resolution audio vs. 16 bit / 44.1kHz
Demonstration of sampling (interactive chart)
Noise perception, detection threshold & dynamic range
Audibility thresholds for SINAD / THD+N measurements
